This disclosure relates to energy management systems for pedestrian safety and vehicle damageability, and especially relates to energy absorber systems that employ plastic deformation.
Increased importance has been placed on methods for minimizing the amount of injury suffered by a pedestrian when struck by a vehicle. Focus has been on bumper assemblies, headlamps. For bumper assemblies, foam resins have been used for energy absorption. Foam based systems typically have slow loading upon impact resulting in a high displacement. Further, while foams are effective to a sixty or seventy percent compression, beyond that point foams become incompressible such that the impact energy is not fully absorbed. The remaining impact energy is absorbed through deformation of a backup beam and/or vehicle structure. Foams are also temperature sensitive so that displacement and impact absorption behavior changes substantially with temperature. Typically, as temperature is lowered, the foam becomes more rigid, resulting in higher loads to attain displacement. Conversely, as temperature rises, foams become more compliant resulting in higher displacements and possible vehicle damage.
With respect to headlamps, actually, due to their placement at the front or the corners of the vehicle, the headlamps of the vehicle are one of the locations most contacted by a pedestrian in an impact, or damaged in an impact with another vehicle. Several different designs have been proposed for minimizing pedestrian injury during an impact as well as minimizing damage to headlamps (e.g., headlights). Some of them require significant structural modifications to the headlamp which increase its volume, weight, and/or cost. Others require structural modification to the chassis surrounding the headlamp area.
In the current competitive automotive market, a major challenge for a design engineer is to reduce component mass, thus reducing the system cost and increasing the fuel efficiency. At present, original equipment manufacturers (OEMs) are very aggressive regarding lower energy absorber mass as the available alternative system provides low cost and low mass solution but with a compromise in performance.
What is needed in the art are energy management systems that meet the desired impact targets at reduced mass (as compared with standard energy absorber systems currently on the market), and, where possible, reduce or simplify vehicle repairs.